Sodium triphosphate and caustic as process aids for the extraction of bitumen from mined oil sands

ABSTRACT

A process of extracting bitumen from oil sand ores having a fines content up to about 60% and a bitumen content higher than about 6% is provided, comprising: determining a dosage (wt %) of caustic necessary to yield a desired primary bitumen recovery; determining an amount of caustic (wt %) and an amount of sodium triphosphate (wt %) which yields substantially the same desired primary bitumen recovery or greater as the dosage of caustic (wt %) alone; mixing the oil sand ore with heated water to produce an oil sand slurry; and adding the amounts of caustic (wt %) and sodium triphosphate (wt %) before, during or after mixing the oil sand ore with heated water to condition the oil sand slurry and to improve bitumen recovery from the oil sand ore; whereby the sum of the amounts of caustic (wt %) and sodium triphosphate (wt %) is substantially equal to the dosage of caustic (wt %) alone.

FIELD OF THE INVENTION

The present invention relates to a process of extracting bitumen fromoil sand ores by adding a combination of sodium triphosphate and caustic(sodium hydroxide) to condition the oil sand slurry.

BACKGROUND OF THE INVENTION

Oil sand generally comprises water-wet sand grains held together by amatrix of viscous heavy oil or bitumen. Bitumen is a complex and viscousmixture of large or heavy hydrocarbon molecules. The Athabasca oil sanddeposits may be efficiently extracted by surface mining which involvesshovel-and-truck operations. The mined oil sand is trucked to crushingstations for size reduction, and fed into slurry preparation units wherehot water and caustic (sodium hydroxide) are added to form an oil sandslurry. The oil sand slurry may be further conditioned by transportingit using a hydrotransport pipeline to a primary separation vessel (PSV)where the conditioned slurry is allowed to separate under quiescentconditions for a prescribed retention period into a top layer of bitumenfroth, a middle layer of middlings (i.e., warm water, fines, residualbitumen), and a bottom layer of coarse tailings (i.e., warm water,coarse solids, residual bitumen). The bitumen froth, middlings andtailings are separately withdrawn. The bitumen froth is de-aerated,heated, and treated to produce diluted bitumen which is furtherprocessed to produce synthetic crude oil and other valuable commodities.

“Fines” are particles such as fine quartz and other heavy minerals,colloidal clay or silt generally having any dimension less than about 44μm. “Coarse solids” are solids generally having any dimension greaterthan about 44 μm. Oil sand extraction typically involves processing oreswhich are relatively high in bitumen content and low in fines content.However, there exists an abundance of “poor ores” which alone yield poorbitumen recovery and consequently cannot be processed unless a highproportion of high-grade, good ores are blended into these dry orefeeds. “Poor ores” are oil sand ores generally having low bitumencontent (about 6 to about 10%) and/or high fines content (greater thanabout 30%). In comparison, “good ores” are oil sand ores generallyhaving high bitumen content (about 10 to about 12% or higher) and/or lowfines content (less than about 20%).

Caustic is used in bitumen extraction to improve bitumen recovery andfroth quality. Caustic promotes the release of natural surfactants frombitumen to the aqueous phase, precipitates divalent cations such ascalcium and magnesium, modifies the electrical surface potential ofbitumen and solids, adjusts the pH, and makes solids more hydrophilic,leading to better bitumen-solids separation. For an oil sand ore, thereis normally an optimal caustic dosage at which the highest bitumenrecovery can be obtained and the optimal dosage appears to be determinedby both the fines content (Sanford, E., 1983, Can. J. Chem. Eng.61:554-567) and the ore grade.

However, the use of caustic may create undesired consequences. Causticis toxic and corrosive, impacting health and the environment and causingscaling on equipment. Compared to the caustic dosage for good ores, ahigher caustic dosage is required for poor ores, but does notnecessarily improve bitumen recovery and froth quality. Causticdisperses fines, hindering fines settling and tailings treatment. Highercaustic dosages induce bitumen emulsification which impairs frothtreatment.

Accordingly, there is a need for a method of minimizing the amount ofcaustic used in bitumen extraction.

SUMMARY OF THE INVENTION

The current application is directed to a process of extracting bitumenfrom mined oil sand ores by adding a combination of sodium triphosphateand caustic to condition the oil sand slurry. It was surprisinglydiscovered that by conducting the process of the present invention, oneor more of the following benefits may be realized:

(1) The combined use of sodium triphosphate and caustic has asynergistic effect, improving bitumen recovery and froth quality in poor(low-grade high-fines) and good ores.

(2) For good ores, the combined use of sodium triphosphate and causticdoes not have any negative impact on processability.

(3) The combined use of sodium triphosphate and caustic requires a loweramount of total chemical addition than the use of caustic alone, and ismore effective at much lower dosages than caustic alone.

(4) The combined use of sodium triphosphate and caustic minimizes theamount of caustic, negating problems normally encountered by use of highcaustic dosages. Sodium triphosphate is non-toxic to humans, animals,and the environment; a scaling and corrosion inhibitor; reduces thechances of bitumen emulsification; and hydrolyzes such that divalentcations captured in chelating form may be released for fine solidscoagulation in tailings treatment; and the hydrolyzed species (e.g., ATPwhich is nutritious and essential to life) may positively impact theenvironment and land reclamation.

Thus, use of the present invention conserves the amounts of process aidsin bitumen extraction, and improves bitumen recovery and froth quality.

In one aspect, a process of extracting bitumen from oil sand ores havinga fines content up to about 60% and a bitumen content higher than about6% is provided, comprising:

-   -   determining a dosage (wt %) of caustic necessary to yield a        desired primary bitumen recovery;    -   determining an amount of caustic (wt %) and an amount of sodium        triphosphate (wt %) which yields substantially the same desired        primary bitumen recovery or greater as the dosage of caustic (wt        %) alone;    -   mixing the oil sand ore with heated water to produce an oil sand        slurry; and    -   adding the amounts of caustic (wt %) and sodium triphosphate (wt        %) before, during or after mixing the oil sand ore with heated        water to condition the oil sand slurry and to improve bitumen        recovery from the oil sand ore;    -   whereby the sum of the amounts of caustic (wt %) and sodium        triphosphate (wt %) is substantially equal to the dosage of        caustic (wt %).

In one embodiment, the amount of caustic ranges from about 0 wt % toabout 0.05 wt % of poor oil sand ore. In one embodiment, the sufficientamount of sodium triphosphate ranges from about 0.005 wt % to about 0.05wt % of poor oil sand ore.

In one embodiment, the amount of caustic ranges from about 0 wt % toabout 0.05 wt % of good oil sand ore. In one embodiment, the amount ofsodium triphosphate ranges from about 0.003 wt % to about 0.009 wt % ofgood oil sand ore.

In one embodiment, the caustic is sodium hydroxide.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings wherein like reference numerals indicatesimilar parts throughout the several views, several aspects of thepresent invention are illustrated by way of example, and not by way oflimitation, in detail in the figures, wherein:

FIG. 1 is a schematic showing, in general, the extraction process forextracting bitumen from mined oil sand ore.

FIG. 2 is a graph showing primary bitumen recovery (%) as a function ofdosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AR.

FIG. 3 is a graph showing primary froth bitumen content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for poor oil sand AR.

FIG. 4 is a graph showing primary froth solids content (%) as a functionof dosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AR.

FIG. 5 is a graph showing combined bitumen recovery (%) as a function ofdosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AR.

FIG. 6 is a graph showing primary bitumen recovery (%) as a function ofdosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AD.

FIG. 7 is a graph showing primary froth bitumen content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for poor oil sand AD.

FIG. 8 is a graph showing primary froth solids content (%) as a functionof dosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AD.

FIG. 9 is a graph showing combined bitumen recovery (%) as a function ofdosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AD.

FIG. 10 is a graph showing combined froth bitumen content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for poor oil sand AD.

FIG. 11 is a graph showing primary bitumen recovery (%) as a function ofdosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AAX.

FIG. 12 is a graph showing primary froth bitumen content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for poor oil sand AAX.

FIG. 13 is a graph showing primary froth solids content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for poor oil sand AAX.

FIG. 14 is a graph showing combined bitumen recovery (%) as a functionof dosages (wt %) of caustic or sodium triphosphate alone, or incombination, for poor oil sand AAX.

FIG. 15 is a graph showing primary bitumen recovery (%) as a function ofdosages (wt %) of caustic or sodium triphosphate alone, or incombination, for good ore AR12.

FIG. 16 is a graph showing primary froth bitumen content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for good ore AR12.

FIG. 17 is a graph showing primary froth solids content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for good ore AR12.

FIG. 18 is a graph showing combined bitumen recovery (%) as a functionof dosages (wt %) of caustic or sodium triphosphate alone, or incombination, for good ore AR12.

FIG. 19 is a graph showing combined froth bitumen content (%) as afunction of dosages (wt %) of caustic or sodium triphosphate alone, orin combination, for good ore AR12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various embodiments of thepresent invention and is not intended to represent the only embodimentscontemplated by the inventor. The detailed description includes specificdetails for the purpose of providing a comprehensive understanding ofthe present invention. However, it will be apparent to those skilled inthe art that the present invention may be practiced without thesespecific details.

The present invention relates generally to a process of extractingbitumen from mined oil sand ores by adding a combination of sodiumtriphosphate and caustic to condition the oil sand slurry.

In one embodiment of the process of the present invention useful inextracting bitumen from oil sand ores, oil sand is mined from an oilsand rich area such as the Athabasca Region of Alberta. The oil sand oremay comprise a fines content up to about 60% and a bitumen contentgreater than about 6%.

FIG. 1 is a general schematic of a bitumen extraction process from minedoil sand ore. The oil sand is mixed with heated water in a slurrypreparation unit. The slurry preparation unit may comprise a tumbler,screening device and pump box; however, it is understood that any slurrypreparation unit known in the art can be used.

In addition to the oil sand and water, sodium triphosphate and causticare also added to the slurry preparation unit to aid in conditioning theoil sand slurry. As used herein, the term “sodium triphosphate” meansthe sodium salt of the polyphosphate penta-anion which is the conjugatebase of triphosphoric acid. Synonyms, abbreviations, and other names forsodium triphosphate include STP, STPP, sodium tripolyphosphate, and TPP.Sodium triphosphate has the molecular formula Na₅P₃O₁₀. Triphosphate isa chelating agent which binds strongly to metal cations such as, forexample, calcium and magnesium. Since polyphosphates are hydrolyzed intosimpler phosphates, polyphosphates are non-toxic to humans, animals, andthe environment.

The amount of caustic is determined by initially testing varying causticdosages to elucidate the optimal caustic dosage which yields a desiredprimary bitumen recovery. In one embodiment, the sufficient amount ofcaustic ranges from about 0.01 wt % to about 0.05 wt % of poor oil sandore. In one embodiment, the sufficient amount of caustic ranges fromabout 0.01 wt % to about 0.05 wt % of good oil sand ore. In oneembodiment, the caustic is sodium hydroxide.

The amount of sodium triphosphate is determined by the optimal causticdosage and type of oil sand ore. In one embodiment, the dosage for eachof caustic and sodium triphosphate does not exceed 0.05 wt % sincehigher dosages are impractical in industrial operations due to costs andefforts to conserve process aids. In one embodiment, the sufficientamount of sodium triphosphate ranges from about 0.005 wt % to about 0.05wt % of poor oil sand ore. In one embodiment, the sufficient amount ofsodium triphosphate ranges from about 0.003 wt % to about 0.009 wt % ofgood oil sand ore.

The sodium triphosphate and caustic may be added to the water prior tomixing with oil sand, directly into the slurry preparation unit duringmixing, or to the oil sand slurry prepared prior tohydrotransport/slurry conditioning. Preferably, the sodium triphosphateand caustic are added to the heated water.

Following the addition of sodium triphosphate and caustic, the oil sandslurry may be screened through a screen portion, where additional watermay be added to clean the rejects (e.g., oversized rocks) prior todelivering the rejects to a rejects pile. The screened oil sand slurryis collected in a vessel such as pump box where the oil sand slurry isthen pumped through a hydrotransport pipeline (slurry conditioning),which pipeline is of a adequate length to ensure sufficient conditioningof the oil sand slurry, e.g., thorough digestion/ablation/dispersion ofthe larger oil sand lumps, coalescence of released bitumen flecks andaeration of the coalesced bitumen droplets.

The conditioned oil sand slurry is then fed to a bitumen separationvessel (also referred to as a primary separation vessel or PSV), whichbitumen separation vessel operates under somewhat more quiescentconditions to allow the bitumen droplets to rise to the top of thevessel and form bitumen froth, which froth over flows to the launder andis collected for further froth treatment. Tailings are either discardedor further treated for additional bitumen recovery.

Exemplary embodiments of the present invention are described in thefollowing Example, which is set forth to aid in the understanding of theinvention, and should not be construed to limit in any way the scope ofthe invention as defined in the claims which follow thereafter.

Example 1

Samples of three poor ores and one good ore were tested (Table 1). Thethree poor ores had bitumen contents ranging from 8.7% to 9.6%, withfines contents from 26% up to 39%. The good ore had a bitumen content of11.9% and a fines content of 16%.

TABLE 1 Classification of Ore Poor Ore Good Ore Designation AR AAX ADAR12 Bitumen, % 9.0 8.7 9.6 11.9 Solids < 44 μm, % 26 39 38 16 Solidsd₅₀, μm 213 92 80 130

Batch extraction unit testing was conducted, using blended processwater, conducting conditioning at 50° C., and testing different dosagesof caustic alone, sodium triphosphate alone, and a combination ofcaustic and sodium triphosphate to assess whether a combination ofprocess aids might have a synergistic effect. The dosages were basedupon the dry oil sand weight (500 g for each test). Initial testsinvolving addition of caustic alone were conducted to find an optimalcaustic dosage for each ore, followed by subsequent tests involvingaddition of sodium triphosphate alone, and in combination with caustic.The dosages for caustic or sodium triphosphate did not exceed 0.05 wt %since higher dosages are impractical in plant operations due to costsand efforts to conserve process aids.

The data were reconciled for material balance using the Bilmat™ program,Version 9.2, 2006 (Algosys Inc., Quebec, CA). The extraction performancewas indicated by the primary, secondary, and wall bitumen recoveries(R_(p), R_(s), R_(w)), which were calculated using equation (1):

$\begin{matrix}{R_{i} = \frac{M_{if} \cdot X_{B,{if}}}{M_{os} \cdot X_{B,{os}}}} & (1)\end{matrix}$

where R denotes bitumen recovery; M is the mass; X is the mass fraction;the subscript i represents either primary (p), secondary (s), or wall(w); and the subscripts f, B, and os stand for froth, bitumen, and oilsand, respectively.

The combined recovery (R_(c)) which is the sum of the primary andsecondary recoveries was calculated using equation (2):

R _(c) =R _(p) +R _(s)  (2)

The total recovery (R_(t)) which is the sum of the primary, secondary,and wall bitumen recoveries was calculated using equation (3):

R _(t) =R _(p) +R _(s) +R _(w)  (3)

Poor Ore AR

For poor ore AR, the primary bitumen recovery was 11.6% when no processaid was used (Table 2). The addition of caustic improved processability.As the primary bitumen recovery did not substantially change when thecaustic dosage was increased from 0.03% to 0.04%, 0.03% was selected asthe dosage for further testing with sodium triphosphate addition. Whenthe caustic dosage was further increased to 0.05%, the primary bitumenrecovery increased to 32.2%.

The primary bitumen recovery and primary froth bitumen content generallyincreased with increasing chemical dosage (FIGS. 2 and 3). The resultsfor caustic alone and sodium triphosphate alone were almost identicalfor primary bitumen recovery (FIG. 2) and primary froth bitumen content(FIG. 3), indicating that sodium triphosphate was as effective ascaustic. The combined use of caustic and sodium triphosphate ispreferred due to having a synergistic effect. The best performance wasachieved with the combination of reagents (caustic at 0.03 wt % andsodium triphosphate at 0.05 wt %) which yielded a primary bitumenrecovery of 53.3% and a primary froth bitumen content of 44.6%.

TABLE 2 Chemical Bitumen Recovery, % Froth Quality Test Dosage, wt %Wall Bitumen Content, % Solids Content, % Series Caustic STP PrimarySecondary Froth Combined Total Primary Secondary Combined PrimarySecondary Combined 1 0 0 11.6 10.4 1.1 21.9 23.0 21.7 15.7 18.4 6.9 30.119.7 0.01 0 13.8 15.0 2.2 28.8 31.0 24.8 18.6 21.2 8.5 32.6 23.0 0.02 015.5 14.8 2.0 30.3 32.3 25.9 17.6 21.2 8.5 31.4 22.1 0.03 0 21.0 17.72.1 38.7 40.8 28.9 19.8 23.9 9.0 29.6 20.5 0.04 0 20.2 17.1 2.7 37.340.0 29.4 21.7 25.3 9.3 31.4 21.2 0.05 0 32.2 18.6 3.1 50.8 53.9 31.122.9 27.5 10.4 28.9 18.5 2 0 0.01 13.9 9.2 0.7 23.0 23.7 21.0 10.4 15.07.3 18.4 13.6 0 0.02 16.3 8.7 0.5 25.0 25.5 25.9 9.8 16.5 7.0 17.4 13.10 0.03 20.5 9.6 0.4 30.1 30.5 29.3 11.6 19.7 6.8 20.9 14.4 0 0.04 26.813.6 0.7 40.4 41.1 32.5 12.4 21.1 7.8 19.9 14.7 0 0.05 27.7 15.4 0.843.1 44.0 33.1 18.0 25.5 8.3 24.8 16.6 3 0.01 0.01 18.5 8.8 0.5 27.227.7 28.6 15.9 22.7 5.6 29.6 16.7 0.01 0.02 20.3 12.3 0.6 32.6 33.2 30.815.6 22.6 5.9 27.0 17.3 0.01 0.03 25.6 18.8 0.8 44.3 45.2 35.9 19.9 26.86.8 29.5 19.8 0.01 0.04 30.5 17.9 0.8 48.4 49.2 38.6 22.0 30.2 9.9 27.919.0 0.01 0.05 29.6 20.7 1.0 50.3 51.3 36.8 23.3 29.7 7.9 29.2 19.1 40.03 0.01 28.5 17.4 0.9 45.8 46.8 37.0 20.1 28.0 7.2 29.9 19.2 0.03 0.0229.9 16.7 0.8 46.6 47.4 37.4 21.0 29.2 9.7 26.7 18.2 0.03 0.03 32.6 20.00.9 52.6 53.6 38.8 24.3 31.6 9.2 28.8 18.9 0.03 0.04 42.7 26.0 1.1 68.769.8 42.5 27.9 35.5 10.5 29.0 19.4 0.03 0.05 53.3 20.5 1.1 73.7 74.944.6 28.3 38.5 12.6 28.4 18.5

For the primary froth solids content, sodium triphosphate alone or incombination with caustic (0.01 wt %) resulted in lower froth solidscontents than the use of caustic alone (FIG. 4). When caustic (0.03 wt%) was combined with different dosages of sodium triphosphate (0.01-0.05wt %), the froth solids contents were similar to those obtained with theuse of caustic alone.

For a fair comparison, the total chemical dosage (caustic and sodiumtriphosphate dosages) should be considered. When sodium triphosphate(0.01 wt %) and caustic (0.03 wt %) were combined, the total chemicaldosage was 0.04 wt %. Compared to caustic alone (0.04 wt %), the primaryrecovery increased from 20.2% to 28.5% and primary froth bitumen contentincreased from 29.4% to 37% (Table 3). The results of primary bitumenrecovery and primary froth bitumen content were grouped by the totalchemical dosages for oil sand AR. For every group at the same totalchemical dosage, the combined use of caustic and sodium triphosphateimproved the primary froth quality. The primary bitumen recovery wasalso improved by the combined uses of caustic and sodium triphosphate,except for the case with a total chemical dosage of 0.03 wt %, at whichthe primary recoveries did not differ.

TABLE 3 Chemical Dosage, wt % Primary Froth Bitumen Group Total CausticSTP Recovery, % Content, % 1 0.02 0.02 0 15.5 25.9 0.02 0 0.02 16.3 25.90.02 0.01 0.01 18.5 28.6 2 0.03 0.03 0 21.0 28.9 0.03 0 0.03 20.5 29.30.03 0.01 0.02 20.3 30.8 3 0.04 0.04 0 20.2 29.4 0.04 0 0.04 26.8 32.50.04 0.01 0.03 25.6 35.9 0.04 0.03 0.01 28.5 37.0 4 0.05 0.05 0 32.231.1 0.05 0 0.05 27.7 33.1 0.05 0.01 0.04 30.5 38.6 0.05 0.03 0.02 29.937.4Similar to the primary bitumen recovery (FIG. 2), the combined bitumenrecovery (sum of the primary plus secondary recoveries; FIG. 5) was alsoimproved by the combination of caustic (0.03 wt %) and sodiumtriphosphate at various dosages.

Poor Ore AD

Poor ore AD processed reasonably well with a primary recovery of 70.2%and a total recovery of 87.7% when no process aid was used (Table 4).The caustic dosage of 0.02 wt % was selected based on the raw primaryfroth amounts obtained from test series #1. Based upon the total bitumenrecoveries, it appears that 0.01 wt % should be the optimal causticdosage; thus, the caustic dosage of 0.02 wt % used in test series #3 washigher than the optimal dosage.

Sodium triphosphate performed much better than caustic in regards toprimary bitumen recovery (FIG. 6) and primary froth quality (FIG. 7).The lowest primary bitumen recovery was 82.9% (sodium triphosphate,0.005 wt %) which was still higher than the highest primary bitumenrecovery of 78.9% obtained with caustic (0.04 wt %). For caustic, theprimary froth bitumen content was about 50% and did not generally changewith increasing caustic dosage. In contrast, the primary froth bitumencontent was higher than 60% with sodium triphosphate. The highestprimary froth bitumen content was 68.2% with sodium triphosphate at 0.02wt %. Sodium triphosphate also reduced the primary froth solids contentwhen compared to caustic (FIG. 8). Sodium triphosphate performedsignificantly better than caustic, significantly increasing the primarybitumen recovery and the froth bitumen content, and reducing the frothsolids content. The overall performance using sodium triphosphate at0.005 wt % was superior than using caustic at 0.05 wt %.

For the combination of caustic and sodium triphosphate, the performancewas generally better than caustic. Significant increases were observedfor the primary bitumen recovery (FIG. 6) and the primary froth bitumencontent (FIG. 7). For the primary froth solids content, the results ofthe combination of caustic and sodium triphosphate were similar to thoseof caustic (FIG. 8).

TABLE 4 Chemical Bitumen Recovery, % Froth Quality Test Dosage, wt %Wall Bitumen Content, % Solids Content, % Series Caustic STP PrimarySecondary Froth Combined Total Primary Secondary Combined PrimarySecondary Combined 1 0 0 70.2 15.9 1.6 86.1 87.7 50.3 11.6 42.1 8.2 24.419.2 0.01 0 73.6 17.9 1.6 91.5 93.2 50.0 13.6 40.2 9.2 22.3 21.5 0.02 070.1 18.2 1.9 88.3 90.3 48.6 11.9 41.7 9.2 26.8 17.7 0.03 0 72.6 16.72.1 89.3 91.4 48.1 12.3 41.9 9.8 27.0 18.4 0.04 0 78.9 11.9 1.8 90.892.7 48.7 12.2 44.0 10.6 26.7 18.0 0.05 0 78.6 12.1 2.2 90.7 92.9 48.611.4 46.0 9.7 34.1 18.9 2 0 0.005 82.9 6.8 2.0 89.7 91.8 62.3 12.2 54.98.3 22.6 29.2 0 0.01 86.1 6.3 1.8 92.4 94.2 60.1 10.9 54.1 8.1 22.9 25.50 0.02 84.5 6.4 1.1 90.9 92.1 68.2 10.9 58.7 8.2 20.7 21.4 0 0.03 85.55.6 1.2 91.1 92.3 62.7 12.4 57.3 10.5 24.8 24.0 0 0.05 83.9 6.9 1.1 90.891.9 63.5 10.9 57.7 8.7 27.2 22.3 3 0.02 0.005 80.8 9.5 1.7 90.2 91.950.6 10.6 46.4 8.5 27.3 20.2 0.02 0.01 77.9 5.7 1.2 83.6 84.8 53.0 10.649.0 8.8 24.0 21.3 0.02 0.02 87.1 4.5 1.0 91.6 92.6 68.5 11.7 61.1 9.719.9 23.0 0.02 0.03 85.9 6.1 1.2 91.9 93.2 58.6 12.3 52.1 10.0 20.3 23.60.02 0.05 88.9 2.7 1.0 91.6 92.6 68.8 10.9 64.9 10.1 22.6 19.4

FIG. 9 shows the results of the combined bitumen recovery. The resultsof all three test series were similar (about 90%) and did not appear tochange with the chemical dosages. However, sodium triphosphate alone andin combination with caustic significantly improved the combined frothquality by increasing the combined froth bitumen content compared tocaustic alone (FIG. 10).

The results of primary bitumen recovery and froth bitumen content forpoor ore AD were grouped by the total chemical dosage (Table 5). Forevery group at the same total chemical dosage, sodium triphosphate aloneor in combination with caustic outperformed caustic alone.

TABLE 5 Chemical Dosage, wt % Primary Froth Bitumen Group Total CausticSTP Recovery, % Content, % 1 0.01 0.01 0 73.6 40.2 0.005 0 0.005 82.954.9 0.01 0 0.01 86.1 54.1 2 0.02 0.02 0 70.1 41.7 0.02 0 0.02 84.5 58.73 0.03 0.03 0 72.6 41.9 0.03 0 0.03 85.5 57.3 0.025 0.02 0.005 80.8 46.40.03 0.02 0.01 77.9 49.0 4 0.04 0.04 0 78.9 44.0 0.04 0.02 0.02 87.161.1 5 0.05 0.05 0 78.6 46.0 0.05 0 0.05 83.9 57.7 0.05 0.02 0.03 85.952.1

Poor Ore AAX

Ore AAX was a very poor processing ore. The primary bitumen recovery waslow at 13.0% coupled with a low primary froth bitumen content at 19.7%when no process aid was used (Table 6). Even at the highest causticdosage (0.05 wt %), the primary recovery remained low at 26.7%, and didnot appear to change with the increased caustic dosage from 0.02 wt % to0.04 wt %. The dosage of 0.03 wt % was thus not necessarily the optimaldosage.

TABLE 6 Chemical Bitumen Recovery, % Froth Quality Test Dosage, wt %Wall Bitumen Content, % Solids Content, % Series Caustic STP PrimarySecondary Froth Combined Total Primary Secondary Combined PrimarySecondary Combined 1 0 0 13.0 8.6 0.6 21.6 22.2 19.7 11.6 15.5 7.8 16.212.2 0.01 0 16.9 11.0 0.7 27.9 28.6 26.0 11.1 17.0 8.6 15.2 12.6 0.02 021.6 11.2 0.7 32.8 33.5 32.1 13.3 21.7 8.1 15.3 12.1 0.03 0 23.0 12.90.8 35.9 36.7 28.4 12.4 19.3 7.5 13.5 10.8 0.04 0 22.9 15.4 1.0 38.339.3 29.4 13.9 20.3 7.8 14.9 12.0 0.05 0 26.7 16.2 1.1 42.9 44.0 34.815.7 23.8 7.0 14.8 11.5 2 0 0.005 20.7 10.4 0.4 31.1 31.5 29.2 13.3 20.96.9 17.7 12.6 0 0.01 26.4 10.7 0.6 37.1 37.7 32.9 11.2 21.1 7.0 16.612.2 0 0.02 36.7 13.4 0.6 50.1 50.7 41.0 13.3 26.4 6.5 18.4 12.8 0 0.0337.8 14.9 0.6 52.6 53.3 41.7 13.8 26.5 6.3 13.9 10.4 0 0.05 41.6 14.90.9 56.5 57.3 42.0 17.3 30.5 8.4 14.6 11.2 3 0.03 0.005 57.7 16.1 3.173.8 76.9 51.9 20.1 38.6 7.9 15.6 11.1 0.03 0.01 46.5 17.9 1.0 64.4 65.439.0 15.7 27.6 8.2 16.0 12.0 0.03 0.02 50.6 17.7 1.2 68.3 69.4 41.0 18.931.5 7.1 14.0 10.1 0.03 0.03 54.2 15.7 2.5 69.9 72.4 47.0 20.0 36.1 8.116.0 11.3 0.03 0.05 59.5 16.1 1.4 75.6 77.0 49.6 20.7 38.3 9.4 18.8 13.1

Sodium triphosphate outperformed caustic, increasing the primary bitumenrecovery (FIG. 11) and froth bitumen content (FIG. 12), and decreasingthe froth solids content (FIG. 13). The best performance for caustic wasobtained at the highest dosage of 0.05 wt %. A similar performance wasachieved at a sodium triphosphate dosage as low as 0.01 wt %. Thecombined use of caustic and sodium triphosphate had a synergisticeffect, yielding greater increases in the primary bitumen recovery (FIG.11) and the primary froth bitumen content (FIG. 12) compared to eithercaustic or sodium triphosphate. The best performance was achieved withthe combination of reagents (the lowest sodium triphosphate dosage at0.005 wt % and caustic at 0.03 wt %) which yielded a primary bitumenrecovery of 57.7% and a primary froth bitumen content of 51.9%. For theprimary froth solids content, the results of the combination of causticand sodium triphosphate were similar to those of caustic (FIG. 13).Sodium triphosphate alone or in combination with caustic improved thecombined bitumen recovery when compared to caustic (FIG. 14). The trendsfor the combined bitumen recovery are similar to those for the primarybitumen recovery (FIG. 11).

The results of the primary bitumen recovery and the primary frothbitumen content for poor ore AAX were grouped by the total chemicaldosage (Table 7). For every group at the same total chemical dosage,sodium triphosphate alone or in combination with caustic (0.03 wt %)performed significantly better than caustic.

TABLE 7 Chemical Dosage, wt % Primary Froth Bitumen Group Total CausticSTP Recovery, % Content, % 1 0.01 0.01 0 16.9 26.0 0.005 0 0.005 20.729.2 0.01 0 0.01 26.4 32.9 2 0.02 0.02 0 21.6 32.1 0.02 0 0.02 36.7 41.03 0.03 0.03 0 23.0 28.4 0.03 0 0.03 37.8 41.7 4 0.04 0.04 0 22.9 29.40.04 0.03 0.01 46.5 39.0 0.035 0.03 0.005 57.7 51.9 5 0.04 0.04 0 22.929.4 0.04 0.03 0.01 46.5 39.0 0.035 0.03 0.005 57.7 51.9

Good Ore AR12

Testing of a good ore was conducted to confirm whether any of theprocess aids might have negative effects on the processability. Ore AR12was a good processing ore, yielding a total recovery of 97.5% when noprocess aid was used (Table 8). Caustic and sodium triphosphate, aloneor in combination, had little effect on the total bitumen recovery, butimproved the primary bitumen recovery and froth quality.

The primary bitumen recovery was about 88% when no process aid was used(FIG. 15). When caustic (0.01 wt %) was used, the primary bitumenrecovery increased to 92.5% and did not appear to change as the dosageincreased. With sodium triphosphate (0.006 wt %), the primary bitumenrecovery reached 92.8%. The combination of caustic (0.01 wt %) andsodium triphosphate (0.003 wt %) yielded a primary bitumen recovery of94.0%.

Without any process aid, the primary froth bitumen content was 52.9%(FIG. 16). The primary froth bitumen content increased with increasingcaustic dosage, reaching 61.7% at the highest caustic dosage (0.03 wt%). With sodium triphosphate (0.006 wt %), the bitumen content was57.9%. The combined use of caustic and sodium triphosphate had asynergistic effect, with the primary froth bitumen content sharplyincreasing as the sodium triphosphate dosage increased. With sodiumtriphosphate (0.009 wt %) and caustic (0.01 wt %), the primary frothbitumen content reached 64.6%. For the primary froth solids content(FIG. 17), there were no noticeable differences among the variousprocess aids.

The effects of sodium triphosphate alone and in combination with causticon combined bitumen recovery are shown in FIG. 18. The results did notappear to change with increased dosage and were within the experimentalerror range. However, the combined froth bitumen quality wassignificantly improved by the combined use of caustic and sodiumtriphosphate (FIG. 19) as was the case for the primary froth bitumencontent (FIG. 16). Overall, the results indicate that use of sodiumtriphosphate alone and in combination with caustic did not have anynegative impacts on the processability of the good ore.

TABLE 8 Chemical Bitumen Recovery, % Froth Quality Test Dosage, wt %Wall Bitumen Content, % Solids Content, % Series Caustic STP PrimarySecondary Froth Combined Total Primary Secondary Combined PrimarySecondary Combined 1 0 0 88.0 7.7 1.7 95.8 97.5 52.9 29.6 49.8 12.3 22.213.6 0.01 0 92.5 3.4 2.1 95.9 98.0 55.7 28.3 53.9 12.8 24.7 13.6 0.02 091.9 3.2 2.4 95.1 97.5 59.3 34.1 57.9 12.8 23.1 13.4 0.03 0 92.2 3.3 2.295.5 97.8 61.7 31.5 59.7 13.1 18.8 13.4 2 0 0.003 91.1 4.7 2.1 95.7 97.853.9 28.9 51.8 13.1 23.5 14.0 0 0.006 92.8 3.1 2.0 95.9 97.9 57.9 27.255.8 13.9 28.3 14.9 0 0.009 93.1 2.7 1.9 95.9 97.7 57.5 25.4 55.5 14.129.1 15.1 3 0.01 0.003 94.0 1.8 1.9 95.8 97.7 58.1 28.9 57.1 13.6 27.414.1 0.01 0.006 94.4 2.0 1.4 96.5 97.9 61.8 25.5 60.0 13.7 25.1 14.20.01 0.009 93.6 1.8 1.4 95.4 96.8 64.6 30.1 63.2 13.1 22.0 13.4

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions. Thus, the present invention is not intended to be limited tothe embodiments shown herein, but is to be accorded the full scopeconsistent with the claims, wherein reference to an element in thesingular, such as by use of the article “a” or “an” is not intended tomean “one and only one” unless specifically so stated, but rather “oneor more”. All structural and functional equivalents to the elements ofthe various embodiments described throughout the disclosure that areknown or later come to be known to those of ordinary skill in the artare intended to be encompassed by the elements of the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims.

We claim:
 1. A process of extracting bitumen from an oil sand ore havinga fines content up to about 60% and a bitumen content higher than about6%, comprising: determining a dosage (wt %) of caustic necessary toyield a desired primary bitumen recovery; determining an amount ofcaustic (wt %) and an amount of sodium triphosphate (wt %) which yieldssubstantially the same desired primary bitumen recovery or greater asthe dosage of caustic (wt %) alone; mixing the oil sand ore with heatedwater to produce an oil sand slurry; and adding the amounts of caustic(wt %) and sodium triphosphate (wt %) before, during or after mixing theoil sand ore with heated water to condition the oil sand slurry and toimprove bitumen recovery from the oil sand ore; whereby the sum of theamounts of caustic (wt %) and sodium triphosphate (wt %) issubstantially equal to the dosage of caustic (wt %) alone.
 2. Theprocess of claim 1, wherein the bitumen content ranges from about 6% toabout 10%, the fines content is greater than about 25%, the causticamount ranges from about 0 wt % to about 0.05 wt %, and the sodiumtriphosphate amount ranges from about 0.005 wt % to about 0.05 wt %. 3.The process of claim 2, wherein the bitumen content is about 8%, thefines content is about 40%, the caustic amount is about 0.03 wt %, andthe sodium triphosphate amount is about 0.005 wt %.
 4. The process ofclaim 2, wherein the bitumen content is about 9%, the fines content isabout 26%, the caustic amount is about 0.03 wt %, and the sodiumtriphosphate amount is about 0.05 wt %.
 5. The process of claim 2,wherein the bitumen content is about 9.5%, the fines content is about35%, the caustic amount ranges from about 0.01 wt % to about 0.02 wt %,and the sodium triphosphate amount ranges from about 0.005 wt % to about0.05 wt %.
 6. The process of claim 1, wherein the bitumen content isgreater than about 10%, the fines content is less than about 20%, thecaustic amount ranges from about 0.01 wt % to about 0.05 wt %, and thesodium triphosphate amount ranges from about 0.003 wt % to about 0.009wt %.
 7. The process of claim 6, wherein the bitumen content is about12%, the fines content is about 16%, the caustic amount is about 0.01 wt%, and the sodium triphosphate amount is about 0.003 wt %.
 8. Theprocess of claim 1, wherein a total dosage of caustic and sodiumtriphosphate is about 0.04 wt %, wherein the caustic amount ranges fromabout 0.01 wt % to about 0.03 wt %, and the sodium triphosphate amountranges from about 0.01 wt % to about 0.03 wt %.
 9. The process of claim1, wherein the caustic comprises sodium hydroxide.